?



H. E. HERSHY & G. A. YANOCHOWSKI.

PARTY UNE AUTOMAHC TELEPHONE SYSTEM.

APPLICATION FILED NOV. 2S, 1913.

1,287,992, Patented 300.17, 1918.

2 SHEETS-SHEET I.

Q j f\.

H. E. HERSHEY :5: G. A. YANOCHOWSKI.

PARTY LINE AUTOMATIC TELEPHUNE svsmw.

APPUCATION HLED NOV. 28,193- M 1,287.992. Patented Dec. 1, 1918.

2 SHEETS-SHEET 2 Mmuim UNITED swung PATENT onnionl GEORGE A. YANOCHOWSKI, OF COMPANY, OI? CHICAGO,

ILLINOIS, A CORPC'RATLION 0F ILLINGHR PARTY-LINE AUTCMATIC TELEPHONE Specification of Applioation fl'led November 28, 1913.

1' '0 all whom it may concern:

Be it known that We, IlARRI 1'1. llrnrnn'i and GEORGE A, YANOUHOWSKI, hoth ciilzacne'; of the United States of Ann-lion and I'Qhl dents of White llaior, Butler (0lm'l', Knn-- sass, and Chicago, Cook county Illinois, re; spectivcly, have invented certuinnrw and useful Improvements in I 111l.y-L1fifi Anto- U'latlfl,TClCPilUllU SAT-linin 01' which the l l'h lmving is n spinrilizcntmn.

Our invention rolalvs in improvanwntn 1n warty-lino automatic tolaphona svstenm mm, has for its object {he provixion of ilnpi'nwii 1110:1115: ix-"hereby one snha'criber may rnll i other subscrihm" on the mine l no. l tofu-re, in party-lino systmns Wlnn'o grow on has been made to permit om snhsvrlhi-r in call another on the same line, it ha? been nocosszu'y to remove the guarding potential from that line in order to perl'nit the con hector switch to call back on the calling lino The object of our invention to proildo means for calling hack on a line \TlljllQ-lli novessil'nting the removal of the guarding; potential in this manner" This and other objecta and features: of our invention will he more readily illl 'lfil stood by reference to thoaocom mn n drawings, in which we have illustrated oz 1 specific enibmliiamni of our invonlion in connoclion with :1 mill-known form of auto matic telephone System11.

Figures 1 and 2 taken. together wllOKV complete connection between a calling Sill)- sl'ntion A and 1: called substation A in a, telonhone system embodying the inrinoiplns: of our invention.

The telephone syslem shown herein is n n anllon'mtic systmn of the Well-known type, in which the connections are 'nstablishod hetwoon the calling and called lines through tho medium of subsgorihorsindividual or line switches selector switches and connector switches. The connection shown is estalr lishcd through the medium of the callin snbscribers lino switch C. first selector second selector F. the connector H and the called nuhscrihcfs line switch C. The lino switch 0 one of a group of similar switchasnhich are controlled by a common mechanism or master switch I) in such a manner that the phingers of all the idle lino swim-hes are always lnanitaineil opposite. the

l of CUIUIOCNPTS is Len-m Palm Pahrntml Doc. 17, 1918.

Eerial N0v 803,524

h wlwtntions i nmv be employed fh (lifiqilanl, ulunzs on the :snum lino nmy ho gnnlwl 1P1. ,ively. Very w-iiJ; mo olelninwl by tho lolia'kYHl' l n rzzn ml. Tin: bolls iiiihwnt NllJrllailUllEfill?) tu'norl or rwisc mingled hi r qmml li: only a oer-- to l.i lciml ol' ringiIt-g current. At the cam ixml oillce means are prm'iiiel'l for prmllwing annoy illr'icrenlx kinds; of ringing current i are sni t itionn upon oneh line. lo, fhrmigh as many (lifl flfil'li grow of L'JHILCI'LOZ ,1 Witches an there an: suhqntinm on lho same, and each group supplied with ringing cnr- Toni of diiinroni. uharavters. Thus, to signal arr: pnrtimlar bllbfa'l on. a line, it is no? my l0 (fill i7 RlP-Tlllilli ol' :2 oonncvfm' in a group which so pliml v-xilh ringing onrrvnt of the proper rhnrnoier lo innernie tho hall at the Fnlntniim: (lSlfLEii. Finch of the diil'nrent Q'T'Ollll: ol' (OEVHLlflIB iihith ha -o nrcess to the same line may be accessible through different lewels of the mcnml si-lecl'oirs. so that the nmnboin of tho ('lifferent substations on each line may he different and the proper group of connectors will be automatically selected wl'n'en the number of any substation called.

ringer 4 and condenser Being an auto matlo substation it is also provided with a suitable call-sending mechanism for c0ntrolling (he anism is represented diagrammatically by a pair of impulse springs- 6 and 7 and an imp'iilse wheel 8, which latter may be controlled in the Well-known manner through the medium of a dial provided with finger holes in such a way that the impulsel springs may be: momentarily separated a number of n line lhrough the automatic switches, which marsh times, correspondin to the respective digits of the number of t m called subscriber. A push button 9 is also provided by means of which the resistance 10 may he cut in series with the receiver 2 and tl'tlIlSfl'lllilLUl 3.

The line switches C and C are of the general type of subscriber-s switch shown in British patent to R. 1V. James No. 26,301 of 1906, resembling more closely, however, the particular type shown in British patent to T. G. Martln No. 1419 of 1910. This line switch comprises, among other details, a plunger (not shown) attached to the end of a socalled plunger arm 21* controlled by a magnet 120. The magnet 120 comprises four windings, namely, a pull down winding 30, a cut-off'or holding winding 39, a line wind ing 20 iind an auxiliary winding 40. The core of the magnet 120 is so (Ul'lSll'U- fllil that the magnetic circuit of the windings. it) and 40 is separate from that of the windings 30 and 39. The winding 30 operates both the plunger arm 21 and the armature ll, while the winding 39 is only strong enough to operate the cut-oil" arn'iaturc 21 and to hold the plunger arm 21 in its operated position after it has been operated. \Vhen the plunger arm 21" is operated, the plunger is forced into the bank of Contact springs, forcing the springs 22, 23, 24 and 25 into engage ment with the springs 26, 27, 28 and 29, respectively. Although only one set of springs 22-29) is shown, each line switch is rovi ed'with a plurality of such sets, eac set forming the terminal of a trunk line leading to a first selector switch E. Each trunk line is connected in multiple to the corresponding springs of all the line switches of the, group which is controlled by the master switch D. The switch U is con trolled by the subscriber through the medium of the line relay 20, as will hereinafter he more fully explained.

The master switch D is of thegeneral type of master switch shown in British Patent No. 26,301 of 1906, referred to above, being, however, of the articular type disclosed in BritishPatent' 0. 1419 of 1910, also re ferred to above. The function of the master switch, as is well known, is to maintain the plungers of all'theidle line switchesin position to engage the terminal of an idle trunk i The first sector E is (if the general ty 0 of selector switch disclosed in United i tates Letters Patent No. 815,321, granted March 13, 1906,-to-Keith, Erickson and Erickson except that the so-called side switch is omit ted,'1n the manner shown in British patent to T. G. Martin No. 10,376. of 1912. Among other, details, the selector E comprises a bank ofcontacts arranged in horizontal rows or levels, which contacts are adapted'to be engaged by a set of wipers 68, 69 and 70 carricd upon a shaft (not shown) which has a vertical movement controlled by the vertical magnet 53 and a rotary movement controlled by lhe rotary magnet (51. The, operations of the switch are controlled through the medium of the (halide-wound line relay 3]. Means for permitting the switch to be restored to normal position are provided in (he release magnet 114-, which, upon energizing, withdraws the retaining pawls from the shaft. The spring contacts 54 and 55 are permitted to close. only when the switch shaft has been raised one or more steps from its lowest position. The relays 37 and 52 are slow cting relays-that is, they deiinergiro slowly after their energizing circuits are broken.

The connector switch H is of the general type of connector switch disclosed in United States Letters Patent No. 815,176, granted Mart-h 133, 11306, to lx'eith, Erickson and llriolcson, the circuits being modified, howea or, to adapt the switch to operate in a tern in which the central otiiee. apparatus is controlled by impulses delivered over the two sides of the line in series, in the manner shown in British Patent No. 1-11!) of 1910, ahrne referred to. Like the selectors, the connector is provided with a shaft (not shown) carrying the \\'1P(,Ir-l 96, 9? and 98, which shaft is controlled by the vertical magnet 94 and the rotary magnet, 102. The usual side switch comprising the wipers 95 103, 104 and 105 is controlled by the private magnet 99in the usual and well-knowir manner. The magnet: 113 is the usual release magnet. The line re1ay79 and the slow acting relay provide the calling line with talking current, and the so-cailied back bridge relay 109 supplies the called line with talking current. The application of ringing current to the called line is controlled by the ringer relay 107.. At Q, there is own a busy signaling machine, the functit 1 of which is to send, under certain conditions, a busy. tone back over the line. A second ringing relay 127 is likewise provided for sending ringing current back over the callin line when a subscriber is callin another su scriber on the same line. The usy signaling machine, as represented herein, comprises an induction coil or transformer-the primary winding of which is included in a local circuit with a battery and an interrupter of high frequency. Through the medium of 'this interrupter an interrupted current is supplied to the primary winding which induces an alternatin current in'the when said" secondary winding, where winding s connected with t e subscribers line, a buzzing sound is heard in his re-' ceiver, Althoughthere is shown a plurality of ringing current,- generators R asso; ciated with the connector H, it will be untici'him'ni Iimi Hwy may be one and the same iwmzm'. Tin: mom iil' lP in r egard to file: iiiim'riipliug dur wa NHL 31 gf'ilv'ltii (iltii'l'ii'iiflll of ihuiuppuraiuzs inning iii-vii giwn, it \viii now he cxpiainei'i ilmr fjwl ih 'ihm m he established imtwcen a rhm I? H ISi .ion A and tho lino of he Ru i lm The numiivr of rho coiling ii-1w in: will Mono to IK" 133 and tire muniic-r of liar iliiUEi ilIlKi 2L. Since the autoimiiu *ViVii iiiiig apparatus (iisi' loaed heroin ia ilv ggmrrul Jifiii known in the art and is iimvr iioii in NH imiriiigiiii m hvrrin roferrwi m it oyvriitinn xi iii we cxpiainmi in a mom '11 Winner. Upon the removal of iiirrr-gc-irvr from the iovii'r'iriiook at the 'ion .a IL'Ljlill' Rory to making :1 cal], rg'iziri g L'il'ifliii is ciosmi through the iirw ii'iiuiiiigi iii of the imiividuili S\\'it(:il Q, iiw iil 'iiii using :5 foiiows: from ground ii through the springs 1'] and ,rmvlucto1 36 iiirmigii the iiizamiion A rominr'ior 17, thrmw'ii iii qirinm 1S and 19 and the wind i115: BM in i-iiirery P This winding 21' upon being mii'l'gi'nlwi, closes; :1 circuit through the puiiwiiiwn winding in series with the mui 'iiry winding 44!. The pun-down coil, RUTH-Fifi tiis plunge:- arm 21*, iimlvirr' operating to close circuits in-n 11 Hm bank of sprlngs to 229, m-

oiiisi 11 ii also operates Hie cut-off armaturr E3 iiiiHilj (iiTiCOIUiGFiiHg the lino wimi' ins? rom tho iiim, The arn'mnu'e 4,1 i005 not iiiii hawk imlneeiiziiviy. however, owing to tin: fast iiiai the inding M] is; still in scriocq mi: iiw puibdmvn winding 30.

Upon iiw yiungg'ur arm 21'- being attrilctezi, the signing i" and 43 nrbrought together to biiill'i'w' Ami iiw ,HEA iim'y windin 40, v1 itirip; iii; armature 41 iufziil back. n aavii zz of tin; armature *1 allows iimi' {or ii holding circuit 50 he iiiiw miimii ahead for iii! subofi' or iioiiiii' 5 ii'iil iln' 9. The ongzigcmoni; of the wring: Q2 and .35 with the springs 2-5 V V n 1 V I I and 25 lfiiiriiilfli}, oximniw the suoscribers iinrw to the line vloy 81 of the sei'ector F. The iinu relay 2&1 of the solo-rim- E "is thereupon eiiergimd through a circuit from ground 1 through the iow-sr winding of the dam relay 31, springs and 32 ofthc rain; 3 through the syringe 29 and 25 to the oomiucior iiL through the subsmiion A to Aim i'li'l'idlli'ilil 177, through the aprilzgs 22 i and 526, through the springs 35 and 36mm! tin: ripper xvi-oiling of the hue rainy 31 t0 iiaii'ery B, c

Tiiv iinv rviny 81., upon 'ovc-omi 1g oner- K i/ML Mos-rs a riruuif through the .iow aetiiigz rvlziy (hi5, circuit extends; from ground through tho spring 49 and its from; v-zniiznj'i. from groom] (i through m jizring--, ER. springs 2T zimi 23 and rgnigzii 1hr imiiimg Wiiisiihs: 39 of the baitviy ii.

Hm winding 3 upon i-nvrp'izi agp iioiiis i110 arm: re 21 and piung'vr arm :21." i1: tiwir oprratcii pow tium iiflvr the rirmlil o1" lil! mil-down iUiiing 3!) is 1110101 by {ha fziiiir [inc-i1 oi H21 iim" armattir 4.1, From Hm sumo point (i A gumling pol -mini is mappiimi if: ilw rimnmtor primuimnk (:oilini'is of' H11- riiiiing: line by way of iil omilirior 4i. 1 Thin (rivcuit r-xtvmis ovvr for riruuii' inst tram-(i in tho bank spring 2! iiwnce owr riianormal conductor 4% to Hliiii primate imuk tlliliil 'i. The exwrgrizai ozi of file, reiny 3T aim r? [)ili'ts H rirmlil for iilu vvrlirzii magma-i i bringing the spring .5 kind 4. illln vngg igzrmenL Ami o'pins [iuvii-viii oi iiiv rolmrwr magnet 11-! at the Hp] ing- 4i; and i7.

'i' hr ri iiing RHiINX'iiJ-l' rim" ngwrniwi i! raiiing devi e for the first ili z it 3 of ii izlilvri nilmiwr, wiimoin' tin; Sllifiihiiflli in pulsv hpri: s (i and T are wpurzximi [\Yil'i. momeiii'zariiy. ouch tinm invoking the uirruit of the seieuor lino reiii The relay 3? of tho solcctnr liqing xiow :u-fiug im-s um; definergzizo during the anmnontnrx inrrrruptions of itgr vim-nit by HEP rviuy 51. and consequmiitiy each time iiil'. izliim' 1-day (ivemergizos, sin impuim i haosmittmi oi'vr the circa t extending from ground ii ii'u'uuggj i lire springs 49 mi 18. 5-0 and 51. LG and 43. reiay 52 and tho vvri'icui lnngmit, 53 to imiiery 13. Til wrtirzii HEHEZUPLTGC iVWi iWO impui ios ow]- tiiis ii -0115i and opemn's to raise tire swifrii shaft and wipvrs two stops tr 2; position opposiw tim sec-om row or iFVii of bank comm-ts :mci. at iim some tizmtho shaflrontroiimi conturts 54: and 55 are closed. The slow iviinfg roiuy 52 is fl!:li]1 mined in ifs onvrgizml'pnfiii'ioii rontiulzolwiy wniie ifllpliifilh are bring! immniitiml in ihe Yerticui nizzgnvr and in its rni-rg'izmi puri- Timi. closes: :1 rirrzlit (ixtvmiing mm grumni G through tin; s11! ings 5b and 57 and tin: i0- i3) 58 1'0 butter I5. The reiiiy 52% upon 01:- Prgizing, forms iiiocking circuit for ii suii' pxtemiiug from g'i-oumi (i at the relay 37,

' 11et-6.1., upon energizing. rotntso the wipers om stop 1155 by opening: the wpring contacts 66 and $9, dlHQOIHiUL'tS ground G from itself and from the r-iay 53H. if Hm first trunk Time of the second low-i is idle. the relay 1 doi nergizcs 'as Soon as the spring contact 59 is opened. If this trunk line is busy, howeven the private wipur 6Q finds the (ow tact it engages providmi with a guarding;

the

ground poh hiinl Whil'ih is il'unsmillml in the relay 58 through us snlin r-z Hi5 and 372 mu} thereby l'n'ments H from c'ivir nm -izing, Thu magnet 1, hnwvvez. defiiwr m1: hm: Hus wiring (*nntart 7-0 i ifl'fiE-Lfiiv; wvflarflahass; Hf \vhothm' the why 58 remains ea mgrizod m not, If Hm why .38 amusing; emrgflm], flu? aim-mt m" 3310 Kuhn um 1 vii be again chasm} :15 5mm m its nrmntmv (1r|1 11':1('k fan enough In vlnsu (ho cummt mu? 59. Th: rotary mumwt wiil. thmma :qmmw in :1 nmmwi simihn? tr: thrii Hf buzz?! .u mi- WHICH film wipvm setup by 5410p mm vine conharts until Hm nmy-g l'oundmi erzmztmrt of an idle trunk linf' is rvzlbhwil by fhn Wipm' 3 whvroupnn the relay 38 c'lvimmgizos The relay upon deiirml'gizing. whofihcx- :Lftm' (3110 02' eneral opemtiwm of the rotary I1agnut. pvmmnently E "21km thecircuit of 11m mngnm 31 and cmwthe circuit mi thu h- \-.'ifuiliug relay 3 whivh Cir-Quit sxcnrl; frmn ground G tin-0mg}! Hm springs 38, mini 53, 52, :1 mi 61' 21ml Lhv lihj. 3% in in bniEm-y I Thu relay 3 lp-(m vnvrg mg; zlisrimmects Thu Sine r-via v 32 fr: an file line and oxtends tiu- Tne :11: um Mon 0 :91 the any conductors shown. fin-nigh the wipers H8 and in [he somn'i svlectm- F. The Einn why 71 of thrswitvh 1' tlwl'mmon b9" mmcs; vnorgizvd and relay F2. whivh in 1211-11, upun mwrggizcing. cmnplntw :1 aim-nil oxiemling from. grown: G", spring 74, wipm (ii? of H10 swi'vh F, spring; (5 5 and H and Hm rUtzy 3-2- m Imbtvr B, TIM: (*iwuii rmainizains fiw :wlzay F31 m-rgg'iwd zxfi oz' iis origin vl'wrgmng mw 1 0i; m IH'IFQUH w Hm us an; 37 whn'h iiuihr'wgixwH 523G111} uifi l? 3; qlim-ulzz'wvt'A-Li fa'mn Hm 331m. a; Mm H'Hltd frmn tho privatv wiper G9 0? Hm svlmin r- R. spying-r 553, springza; 2? v} "22; and tin:- hnlding vni'i 3i of H10 151m adiiqh U M bub Em-y B and also frmn the q 23 Hmmpjh the cmnlnctm' M in if)? mnnvstaw pi-hum bank mntau't minim} with file sim- :WLiHh (I 'lxirhzii'mii kcvpe thv lwhiiaag mil 89 0f HIP line switch l'nvl'gfxwd 2: m1 A 150 l-zevfs a guarding putfintin] upun Hui! cunn-y-ci'ur pri "aha hunk rrmmu-t xisrqn jiawi with div lino switsh C. In :ulditiun, flu" rainy T2 of thv. selm'tor F also mninhnins a gum-ding gyrnuml poh'miai upon the primtv hank mmnch 0f the trunk line in Hw imnka (If Ex "Em-- tor switchns E which haw iifl' m 52%;! trunk lino.

following zia'miiz 1mm gym: :6; ihmiigh Hi9 fine rvizw Y (we? iim hmvy conductor to and through the l-Hilifiiiitififi mac-39w and war the min)" Ehiaim mm;

ground 3' 17 ing 3Q h:

through ihe conductor -i (0 *wrucwl magnet n its ernv that imp;

cm ziri i in 5W. Whivh, 11pm; deinm L 133, rotary magnet 102 and the side switch wiper 95'(in second position) to battery B. The relay 93operutes in response to the im' pulses'for this digit in the same manner as for the previous digit to cause the private magnet 99 to advance the side switch to third position. By the engagement of the side switch wipers 103 and 1 with their third'position contact points, the line connection-is completed with the called line. Upon the engagement of the wiper 105 with itstlnrdosition contact point, a circuit is completer through the cut-0. T winding 39' of the called line switch. The circuit extends from ground (1' side switch wiper 105 (in third position), private'wiper 97 and the cut-off winding 39' to battery Br The cutas winding of the called line switch, a. )Ol't energizing, operates to disconnect the line relay from the called substation. The connection of ground G with the connector Jprivate bankcontact of the'called line prevents the called line from being seized by some other connector switch. By the engagement of the side switch wiper-95 with its third-position contact point, the circuit of the ringer relay 107 is closed; This circuit extends from ground G" through the interrupter 106, ringer relay 107 and the.

springs 108 and the side switch wiper 95 (in third position) to battery B. The ringing relay disconnects the calling line from I the called line andbridgcs the ringin current generator R across the called line to signal the called subscriber. The. ringing relay is ener "zed only intern'iittentl'ythrough the ma i Upon the respon sc of the called subscriber his line is provided with talking current windings of the back-bridge upon energizing, the ringer cut-off through the relay 109, which relay, closes the circuit through relay 110.. i ground G" through the side switch wiper 105 (in third position), springs lllaud the ringer cuebfi relay IIQ to battery B.' The relay 1'10, upon energizing, interrupts the circuit of the ringing relay 107 at the springs 108 and closes itself through the springs 112, independent of the springs 111.

After the conversation connection is released by the the receiver at the calling usual inanner. I

It'having been explained how one subscriber establishes connection with another completed, the hanging up of subscriber and releases the same, it will now ,be explained how a conncctiorris prevented from beingv made with a busyline. If the called/number is busy, there will be a guarding potential upon the connector private bank contact, just as explained in connection with the line switchC. Thii connector private wiper 97, upon engaging this guardvin calling the substation.

private bank terminal 122 um offthe interrupter 10G.

. of current through The said circuit extends from a locking circuit forpreriously explained. When the substation in the gageincnt, a "Hl'lllt 1S closed from ground relay first wipe: J7, side switch wiper 105 (in second position). springs 116 and 115. busy relay 117. springs 118 and 100 and the private magnet 99 to battery B. The husy relay 11?. upon energizing, closes the contact of springs 112.) and a busy tone is sent back to the calling subscriber from the busy machine Q by way of the side switch wiper 104 t in second position), thence to the calling substalionto battery B, whereupon the receiver is replaced. on the switch-hook and the connector is released in practically the same manner as described above.

It will now be explained how the substation. A can call the suhsta ion 2233, the said suhstation'bcing on the same. line as the substat on A. 2233 being 2 indicates that the bells of substation 2233 are designed to be rung from the same group of connectors as were used scrihcr at substation A removes his receiver and vallsthe digits 2---2-2- 3 in the same manner and with the same results as explained for the number2222, except that now the wipers of the connectors H are resting upon the bank contacts 121., 122 and 123, which are the connector bank terniinals oi"- the line switch C. ()f course-the will be grounded, as above (2. .lained, and this will cause the connector- II iff) throw the busy tone back to the substation A, but the's'uhscriber at substation A, knowing that he isralling a party upon his own lineydisregards the busy signal and presses the button'fi), hereby cutting the-high resistance 10 in series with his receiver and transmitter. This added resish ance'in the line circuit: so reduces the flow the relays 79 and 80 that the relay 80 falls. back until the springs 124, 125 and l26are in contact. Thesprin s 81 also remain in contact at this time. Tlie while the springs 1249311 81 are weak, the spring hiwinakes contact with the spring 8!). -This opens the circuit of the relay 87, which, upon ilcncrgiziug,causes the release of the i'roi'inector switch H in thefinauncx" springs 124, 125 and 128 of the relay 80 are in enti, interrupter 106, auxiliary ringing rela I27 and the springs 125, and 124 to battery-B. It. Will be seen that when the pulls up, the springs 124,125 and 126 are in cimtart too short a time for the relay 127 to energize, but upon their coming into contact. as above explained, the- 2222. The suhllio spring 1.26 is a heavy spring and adjusted, with stiff tension,

The relay 79 falls back until circuit. through the auxiliary ringing relay 127 causes it in be energized intermittently,

thus culiingoil the relays Ti) and 80 and throwing current from tiiegenerator R out n n theline A torin contact with the springs 130and 132, re

spectively, upon the detnergization of the relay 127 before the springs 128 break contact, thus insuring that ground G is again placed upon the release trunk before ground a G". is removed: The subscriber at substation Aavill hear the rin in current ro- I I a 'I g ected upon his line. through his receiver 2 in series with the transmitter 3 and high resistance 10. In this way he will be advised that the called subscriber is being run and the secession of the ringing current wi inform him that the called subscriber has answered, whereupon he will release the button 9 and converse with the subscriber at substation 2233 in the'usual nuinner. The removal of the receiver at the substation 2233bridges the receiver and transmitter directly across the line and this increases the How of current to such an extent that the relay 80 again entirely energizes andopens the' circuit of the auxiliary ringing relay.

127 at the springs 124, 125 and 126. The relay 79 again also energizes and upon do ing so closes the circuit of the relay 87, which is withoutetlect at this time. Upon completion of the conversation, the last subscriber to hang up opens the circuit of the relays 79 and 80. The de'nergizu'tion of the relay 79 opens the .circuit of the relay 87, which is without effect at this time. The dethiergizatiou of the relay-80 removes the ground G from the release trunk and ctl'ects'the release of the selectorsE and F and of the line switch C in the same manner as described above.

It will thus be seen that we have devised a Very ellicient system in which one party can call back on the same line without necessitating the removal of the guarding potential from that line. In other words, the guarding potential for the'line'is maintained at all times to prevent a subscriber on another line from obtaining connection with that line, and yet the calling party is 'enabled to ring back on his line in order to signal the desired called subscriber located on the same line.

(Vhile we have illustrated a specific em-- bodinicnt of our invention in connection with one specific form of automatic telephone systcm, it will of course. be understood that various changes and modifications will readily suggestthemselves to those skilled in the art, and that. our intention is the bell of substa-. tron 2233. The energization of.jthe relay,

equally as well a'da t ed for use in connection with various ot er forms of automatic or semi-automatic telephone exchange systems.

What we claim as our invention is '1, In a telephone system, a party-line, a'

connector switch, means for extending a connection from said line to saidfconnector switch, means for lacing a guarding potential on said line when a call is initiated, and meansfor operating said connector to seize said line and .to automatically signal a second station on said line without removing said guarding otential.

2. In a teleplionesystem, a calling and a called line,'a' connector switch, a progres-.

sively movable wiper for said switch, and means in said connector switch for automatically applying ringing current to said calling line oyer a. circuit excluding said wiper, and to sald called line over said wiper.

3. In a telephone system, a subscriber-s 'line, a connector switch, meansincluding a trunk'line, for extending a connection from said line to said switch, and a ringing relay for separating said trunk from said connector;

4. In a telephone system, an automatic progressively movable switch, a line terminating in said switch, a set' of wipers for said switch for extending connection therefrom. a signaling relay in said switch asso' .clated with said line for pro ecting signal 1111; current over said line, and a signalingrelay in said switch associated with said wipers for projecting signaling current over said wipers. a

5. Ina telephone system, a line, an automatie progressively movables-witch, line termmals associated with said switch, wipers ios associated with said terminals, means for,

operating said switch to move said wipers' into engagement with saidterminals, releas equipment for disconnecting said wipers.

from said terminals after the connection is made, a signal for sa d line, a source of signaling current, and a signaling relay forsald connector for proyectmg signaling current to said line after the switch has released, to operate said signal.

6. In a telephone system, a line, an auto-- matic progressively movable switch, line terminalsassociated with said switch, Wipers associated with said terminals, operating magnets for said switch to move said wipers into engagement with said terminals, a release magnet for disconnecting said wipers from said terminals after the connection is made, a signal for said line, a source of signaling current, and a signaling relay for said connector for projecting signaling current to said line after the switch has released, to

' operate said signal.

mid line. an automat c trunking switch, imam fur rcnmcting 1110 line with the swish ri." .shizl first terminal and for open M111 5 said :HHiiri m iimi fluz'lerzuina! fur inking lifi line, 11 5.571111! for said. iine and 21 sign. rmitrni'i ng why in mid switch for (iiflldi in Mil? siigmli. a busy test circuit for Hair; ine. 11111111111 fur applying May when-- t n! 1.11 11151 viii-111i, w -11 Hie line and the f-i'n'iiiii 111-1: cmiuerteii and fur niainmining sii-j' puimi'ml appiimi said 1.11151 1.1241 (iisuit iiiiiii :1 Mr thi- 31 9:33.1 is operufeii.

1' 1 ii1i ;:F1=i muinn 21 51.12. a busy tux-t circuit 111" mid iii" :1 culling terminai W511 iim-y :1 i-121 11; for cuiiiiig said :111 :mlmzmfir 1 grcssiwlj; mu able mum-i1 fer finding hu ivrminai for calling said H111 111mm fu :qmiying :1 guarding porfmthli to .r-aiii i1 mgr (-iri-uit \iii Qfiiti fix i, tut'nimii iivfm'u ii six-111111 terminal is fuum! um] fur ma ntaining 551M putantizii 1111;111:911 1310mm, :1 1 w11i fur 1 1! iimn 11021113 for z pgflying; signaling rurrr-nl' to said lino fur npornting mid igiwi .iflvr I19 terminal is (11111111 :1 '11} viif'imut rmmving H10 111M 11- tikii 13111111 i310 that u mliii.

in :1 ti-irg iwne v 1'111: 11 line. :1 forminui i'rn 'il ii iimfur mining: from s. (1 IN. :1 tvrminn! For Hiliii I111; form-111N115: said i'inc. :1 ig1m! im' -11i1l lim v.11 imiiinmtir ZHUQ'HS- siuiv 111111111111 viii-F1 i'ni finding Kb! 501? Otili tvrmina! 11111! 5311- fiiljliiiiiiigj tiw iim" 11v projwting riymiin g ('iHithE in 1111' 15111: F11

P1115113 zuu'ierthe mantra of the line for bridginp: saidi switching upparatm between the iwn terminais. releasing; mechanism for said swim-hing appai-at automatically con-- trolled to release 1:5. switching apparatus when the bridge min ilvted, a signal for mid iimn a sourere 9f signaling current associated. with Hiiii'i imixumnfzin switching z1pparat-us c0111 miirzri fmm the line tin-0111311 said switching 113:1 .1 his to direct signaling curruit to the ii? 1y may of the mid first terminal fur a m-rating said signal, aft-er the switching appa 11mm ire reinased.

13. In El ieiepiiume s x-stony a line, a branch for said line far wiiing tin-refrum, a branch for said lime far railing timi'sto, mztmnatic switching: ilppliiiillih limited hetw on said branches said r-1f(?i!i!l;'{ apparatus 1m der the minim! [9f the line for bridging said writrising: alppallflifln' iMlYufifl the" two ln-zunziles 11 signal for mid line. a plm'aiiny 0f SUIHTTH of 1 11111511; i-nrrent aswciated 111111111 1 for whiting 11110 of said siulzrrcs of rignuiing LIU'IL'HL *Iliti sviocieii ig11aling 0111112112 i-mi'tmiimi from the line ihrfiugh Hili'fi V 1\itui1i11 iiyi mrrifius to iiirurt signaling IJHH-Hi' to H11- iin mm the wimrtmi source UV v.11 11f F 1 Sfiid first, idsliiifiui 591' 01111171 iug mil? figimi.

H. in :1 tvivg'iiii'inv .-'1 1T U.El :1 plurality (if lines. 111mmv iHFiiH iiiL! 1111 nutrmmfi'ic v wiiui1 fu 050111917151 :1 iwaiiingz (111 (if $111k! lines with :1 011311 1 11110111" min iinv separate ri11ging rviays 1'11 smiii --wi1fvi1 for iguui'imr the ruiiini H119, 1111-11111 Hr ingihg (11 113 1;? mid wh m 111111 11: 1 \1111 1: H11 cuiinii iizm is nisn H111 ('Hliiilfl 15M. and NHHHH for bringing the uihier 11f mid roinw intu use \viivii 'tiiu lfzllleei iiiw i 111*? Q11} culling H1112 1-3 in :1 tvivpiimw 1 111-111, :1 piurzilit y of H1195. :1 wmnvvting link fur uniting any tun 01' said iimw in 111111 301 51m. fixml :nni mova le h riuimiis 11$ oppmiir vmis of said link. 1111 :1115 for warm-ting 1; 1113511 Jim: with Iiliti iixeri tili'l'lii351i Li mum-e of sig 'sziriing vim-mat. inc-21m fur minim-ring =1i1i Hfllilfifi with the (iliit'ii 51m 11:1 mid fixui. terminal 1f tiiv ruiimi iimis :liHU U11: raiiing line, and 111L111: for minim-ting mid 50111111 with the] cailrri iinre viimaid mm'ulilii l-!'J1li!2:liii the milled line is not the wiiiiug iiuv 1G. in :1 triephnmw 1141 1 1 :1 nilrriziit (11 fines. :1 rmznuriiu z link 1 111-1115, :17 1-106: nf iii'fiiilmib zit 11111. umi 1' 111]! link for ("011 nwtiun in mining; iinus. :1 sot of terminals at ti1== ntiirr 1111i 11! will, iiiik for (111111606011 11 mih-ii [21103. menus fur cnnmwting 11 111iing line with mid izwi' act, (if tillliilzilifi a min-1'0 [1f rimming; cu l-vim and moans c0nimiiwi 011-1- ifm fziiiing iirm far ciimmcting 5:151! .HGIEII'G, w th vitiwr wt of im'inimiis m H111 ax illhiljii 11f i311: ntiwr SOL 17. In a 53213111 121 whim. :1 Iiiiil'iliiij of M111 5, 1 uonriecilng Eiiik rimuii 1119:1113 fer 

